1. Field of the Invention
The present invention relates generally to three-dimensional templates and, more particularly, to a three-dimensional design template used for designing, evaluating, and measuring human occupant accommodation and seating in a seated environment.
2. Description of the Related Art for Automotive Vehicle Seats
Automotive vehicle seats have three primary functions: (1) position an occupant for a driving task; (2) support comfortable healthy sitting postures; and (3) protect the occupant upon vehicle impact. A deformable pad on a mechanically adjustable seat frame accomplishes the first function and the second function is accomplished through the geometrical and mechanical properties of the deformable pad composed of one or more padding, suspension, and upholstery. The third function is accomplished by seat and restraint systems to restrain the occupant during a vehicle impact. The first two functions determine the greatest portion of the occupant's perceived level of comfort. Position has been considered a primary determinant of occupant comfort and posture has been relegated to the occupant's ability to adapt to the vehicle environment. A major function of seat position and its supporting surfaces is, however, to support the occupant's posture. Thus, there is a need in the art to provide a design tool for automotive vehicle seats.
It is known in the automotive manufacturing industry that seat design relies on a tool built in the early 1960's to represent the position of the hip joint (SAE H-point) and leg links for locating the position of the vehicle occupant in the occupant compartment of an automotive vehicle. This tool is known as “Oscar”. Oscar is not constructed for seat design but has become an industry standard because there is no suitable tool that identifies the location of the occupant's torso in the seat. As stated in Volume IV, 1984, SAE Handbook as follows:
“The devices described in this standard are intended for applications concerning seated driver side or center occupant accommodation spaces only and are not to be construed as instruments which measure or indicate occupant capabilities or comfort.” (p. 24–27).
The tool known as “Oscar” is disclosed in U.S. Pat. No. 3,147,617 to Kaptur, Jr. et al., which describes an accommodation checking device. The accommodation checking device is positioned on a seat in order to determine whether the seat and the body are suitable for accommodation of a known predetermined human body. The accommodation checking device includes a seat pan having a lower outer surface thereof shaped to conform to a lower surface of upper leg portions or buttocks of the predetermined human body. The accommodation checking device also includes a back pan having a rear outer surface thereof shaped to conform to a contour of an outer surface of a back of the predetermined human body. A pivot provides a pivotal connection between the seat pan and the back pan. A member is marked off in angular degrees on each side thereof and other members include pointers to register with the numerals on the member. However, these angular degrees are for joint angles and do not indicate skeletal landmarks relative to a seated human body occupant.
Contour shape of an unoccupied seat is an important aspect of seat comfort, but an interface between the seat and occupant is defined by a deformed shape of both the seat and the occupant. The deformed contour of the human body is difficult to measure. In order to understand the shape between the occupant and the seat, a tool is needed that allows for accurate measurement of the deformed contour of the occupant, with minimal effect on the interface between the seat and occupant.
It is known that body loads are transferred to the seat through the skeleton of the human body. Therefore, the location of bony landmarks on deformed contours is needed to improve seat design.
Contour shape has been measured directly by attaching displacement meters through the seat to the contact surface, but this method damages the structure and therefore changes the mechanics of the seat. Plaster casts have also been used to obtain the deflected tissue shape with the assumption that the shape is plaster does not change the shape of the body and is unchanged during the shift in load as the subject moves from the seat. However, the plaster cast technique cannot be used to study the interaction between the body and the existing seat nor is it suitable to measure the effect of a deformable seat on the shape of the occupant. Therefore, there is a need in the art to provide a design template of the human body having cross-sectional shapes for biomechanical design that are based upon measurements of the deformed shape of the occupant due to the reactive loads of a deformable pad as those used in the automotive vehicle.